diff --git a/src/test/java/com/github/nkzawa/engineio/client/Connection.java b/src/test/java/com/github/nkzawa/engineio/client/Connection.java
index 48693ca..9d9b98b 100644
--- a/src/test/java/com/github/nkzawa/engineio/client/Connection.java
+++ b/src/test/java/com/github/nkzawa/engineio/client/Connection.java
@@ -9,9 +9,12 @@ import java.io.InputStreamReader;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.*;
+import java.util.logging.Logger;
 
 public abstract class Connection {
 
+    private static final Logger logger = Logger.getLogger(Socket.class.getName());
+
     final static int TIMEOUT = 10000;
     final static int PORT = 3000;
 
@@ -22,7 +25,7 @@ public abstract class Connection {
 
     @Before
     public void startServer() throws IOException, InterruptedException {
-        System.out.println("Starting server ...");
+        logger.fine("Starting server ...");
 
         final CountDownLatch latch = new CountDownLatch(1);
         serverProcess = Runtime.getRuntime().exec(
@@ -38,10 +41,10 @@ public abstract class Connection {
                     line = reader.readLine();
                     latch.countDown();
                     do {
-                        System.out.println("SERVER OUT: " + line);
+                        logger.fine("SERVER OUT: " + line);
                     } while ((line = reader.readLine()) != null);
                 } catch (IOException e) {
-                    e.printStackTrace();
+                    logger.warning(e.getMessage());
                 }
             }
         });
@@ -53,10 +56,10 @@ public abstract class Connection {
                 String line;
                 try {
                     while ((line = reader.readLine()) != null) {
-                        System.err.println("SERVER ERR: " + line);
+                        logger.fine("SERVER ERR: " + line);
                     }
                 } catch (IOException e) {
-                    e.printStackTrace();
+                    logger.warning(e.getMessage());
                 }
             }
         });
@@ -65,7 +68,7 @@ public abstract class Connection {
 
     @After
     public void stopServer() throws InterruptedException {
-        System.out.println("Stopping server ...");
+        logger.fine("Stopping server ...");
         serverProcess.destroy();
         serverOutout.cancel(false);
         serverError.cancel(false);
diff --git a/src/test/java/com/github/nkzawa/engineio/client/ExecutionTest.java b/src/test/java/com/github/nkzawa/engineio/client/ExecutionTest.java
index 244b383..0a2352a 100644
--- a/src/test/java/com/github/nkzawa/engineio/client/ExecutionTest.java
+++ b/src/test/java/com/github/nkzawa/engineio/client/ExecutionTest.java
@@ -7,6 +7,7 @@ import org.junit.runners.JUnit4;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.util.logging.Logger;
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
@@ -14,6 +15,8 @@ import static org.junit.Assert.assertThat;
 @RunWith(JUnit4.class)
 public class ExecutionTest extends Connection {
 
+    private static final Logger logger = Logger.getLogger(Socket.class.getName());
+
     final static int TIMEOUT = 30 * 1000;
 
     @Test(timeout = TIMEOUT)
@@ -38,7 +41,7 @@ public class ExecutionTest extends Connection {
                 new InputStreamReader(process.getInputStream()));
         String line;
         while ((line = input.readLine()) != null) {
-            System.out.println("EXEC OUT: " + line);
+            logger.fine("EXEC OUT: " + line);
         }
         process.waitFor();
         assertThat(process.exitValue(), is(0));
diff --git a/src/test/resources/logging.properties b/src/test/resources/logging.properties
index b1a5c7d..9ffa15b 100644
--- a/src/test/resources/logging.properties
+++ b/src/test/resources/logging.properties
@@ -1,7 +1,7 @@
 handlers = java.util.logging.ConsoleHandler, java.util.logging.FileHandler
 .level = ALL
 
-java.util.logging.ConsoleHandler.level = FINE
+java.util.logging.ConsoleHandler.level = INFO
 
 java.util.logging.FileHandler.level = ALL
 java.util.logging.FileHandler.pattern = ./target/test.log